The
term Torx head refers to a particular type of fixing system. Torx
head bolts and screws are often used in automotive applications
and come in a variety of different sizes.

The six pointed design of the Torx head allows for a large amount
of force to be applied without the need for a large head, like on
a conventional hexagonal bolt.

One drawback to the Torx system is that if used improperly or with
an incorrect sized bolt head and driver combination they can be
quickly rounded out making extraction difficult. When using Torx
head bolts ensure you are using the correct sized driver.